Chipper knife grinder



March 28, 1961 STANDAL 2,976,649

CHIPPER KNIFE GRINDER Filed May 15, 1959 4 Sheets-Sheet l INVENTOR.Geozye M Sfzmaal Y March 28, 1961 STANDAL 2,976,649

CHIPPER KNIFE GRINDER Filed May 15, 1959 4 Sheets-Sheet 2 March 28, 1961STANDAL 2,976,649

CHIPPER KNIFE GRINDER Filed May 15, 1959 4 Sheets-Sheet 3 d- 65 42 I O7] 70 U INVENTOR;

March 28, 1961 G. M. STANDAL 2,976,649

CHIPPER KNIFE GRINDER Filed May 15, 1959 4 Sheets-Sheet 4 K INVENTOR. BY660/}? M Szfaxzaa/ 2,976,649 Patented Mar. 28, 195i- CHIPPER KNIFEGRINDER George M. Standal, Chemainus, British Columbia, I

Canada Filed May 15, 1959, Ser. No. 813,393

4 Claims. (CI. 51-55) My invention relates to a chipper knife grinder.It is particularly directed to a grinder so arranged as to grind achipper knife which requires one ground face to be in a plane andanother ground face to be curved. It is the purpose of my invention toprovide a grinder of this nature wherein both faces are ground atcontrolled rates, pre-set by the operator, and wherein the grindingwheels are advanced toward the work from the same base control to'assure maintenance of the proper ratio of grinding between the curvedand plane surfaces.

Other objects and advantages of my invention will appear from thefollowing description and the accompanying drawings wherein a preferredform of the invention is shown.

In the drawings:

Figure 1 is a front face view of a chipper knife grinder embodying myinvention;

Figure 2 is a fragmentary bottom plan view of a portion of the grinder;

Figure 3 is a plan view of the grinder;

Figure 4 is a side view of the grinder looking at Figure 1 from the leftside;

Figure 5 is a rear face view with parts broken away of the grinder;

Figure 6 is an enlarged fragmentary bottom view, looking at Figure 1from the line 66;

Figure 7 is an enlarged sectional view taken on the line 7-7 of Figure3;

Figure 8 is a sectional view taken on the line 8-8 of Figure 7;

Figure 9 is a bottom plan view of a chipper knife that is sharpened bythe grinder; and

Figure 10 is a fragmentary sectional view taken on the line 1010 ofFigure 6.

My invention is embodied in a grinder wherein the knives 40 are mountedon a rotatable head 2 which is supported by its drive shaft 3. The shaft3 is mounted by two bearings 4 and 5 on standards 6 and 7 that extend upfrom a hollow base 8. A main motor 9 is mounted on the base 8 and isconnected by a shaftlll to a speed reduction gear unit 11, also mountedon the base 8. The unit 11 has a shaft 12 provided with two sprocketwheeis 13 and 14 which drive chains 15 and 16 respectively. The driveshaft 3 has a sprocket wheel 17 thereon which is driven by the chain 15.The chain 16 extends through the top 8a of the base 8 and drives a wormshaft 18 that is suspended in bearings 19 and 20 from the top 8a.

The worm shaft 18 has a worm 21 thereon which drives a worm gear 22 thatis fixed on an upright shaft 23. The shaft 23 is rotatably supported ina pedestal 24 that has a base plate 25 bolted to the base 8. Beneath thegear 22 the shaft 23 has a crank arm 26 fixed thereon. The crank arm 26has a rod 27 pivoted thereon that connects to a crank arm 28 fixed on ashaft 29 that is rotatably supported in a pedestal 30. The pedestal 30has a base plate 31 that is adjustably mounted on the base 8 by bolts 32that extend through elongated slots 33 in the base 8 and elongated slots34 in the plate 31. The shaft 29 supports a grinding unit 35 which willbe described more fully hereinafter.

The shaft 23 also has a crank arm 36 fixed to the upper end thereofabove the pedestal 24. A rod 37 is pivoted on the crank arm 36 andconnects to a grinding unit 38 which will be described more fullyhereinafter. t

The knife 40 which is .to be ground by this grinder is illustrated inFigure 9. It comprises a base portion 41 and an upturned nose portion42. The two portions 41 and 42 are curved where they join. The faces 41aand 42a have to be ground in such a fashion as to present a cutting edgewhich has the peculiar configuration shown. The nose portion 43 of theedge is forwardly of the junction 44 between it and the edge portion 45on the base portion 41 of the knife. The nose portion 42 may be oneither the right hand or the left hand side of the portion 41.

The head 2 carries a plurality of mounting blocks 46 for mounting theknives 40. As shown, there are seven such blocks bolted to the peripheryof the head 2 which is disk-like with strengthening ribs 2a and a hub2b.

Each block 46 has provision for mounting the knives 46, one a right handknife and the other a left hand knife. The block 46 has a two channelledprojection 47 thereon which projects in a direction parallel to theshaft 3 of the head 2. The projection has its channels 49 and 59 openoutward so as to receive the knives 46 therein. One channel is for righthand knives 49, the other is for left hand knives. The channels 49 and 5are closed at the back as indicated at 51 to control the amount a knifeprojects beyond the face of the channel. In each channel there is aclamp bar 53 which is carried by the front wall 54 of the channel on acap screw that can move a limited amount through the wall 54 and isthreaded into the bar 53. The walls 54 are also threaded to receive twoset screws 55 and 56 which press the clamp bar 53 against a knife 40seated in the channel. The projection 47 and the clamp bars 53 arebevelled across the front to parallelism with the plane of rotation ofthe head 2.

It will be appreciated that in view of the peculiar configuration of theknife 40 the channels 49 and Si do not extend radially with respect tothe head 2. They are set .at such angles to a plane perpendicular to theaxis of rotation of the head 2 and to a radius from the head hub 21)through them that the proper slope of the cutting edge 45 on the knife40 Will result from passing a grinding wheel face across the knife face41a in a plane perpendicular to the axis of rotation of the head 2. Thechannels are also set at such an angle that the nose face 42a can berounded by grinding. As shown, the nose faces 42a of both right hand andleft hand knives 4d are directed so they curve toward the back of theblock 46 from the plane of the face 41a which is parallel to the backface 20 of the head 2.

The grinding unit 35 is the unit which grinds the nose faces 4211. Itcomprises a supporting arm 58 fixed on the shaft 29, a mountingstem 59on the arm 58, and a platform 60 on the stem 59. On the platform 60there is a slidably mounted motor 61 which carries a grinding wheel 62.It will be appreciated that, since the shaft 29 can be shifted, byreason of the adjustable mounting of the pedestal 30 provided by theslots 33 and 34 and the bolts 32, the position of the axis of the shaft29 with respect to the path of the nose of a knife 40 clamped to thehead 2 can be pre-set correctly. After that the endwise movement of themotor and grinding wheel toward the work is accomplished by sliding themotor 61 on the platform 60.

The means for sliding the motor 61 on the platform 60 comprises a shaft63 which is journalled in the plat form 64) at its ends and which has athreaded portion 64 that is threaded in a depending boss 65 on the motorbase 61a. A handwheel 66 is fixed to the shaft 63 and has peripheralgear teeth 67 which mesh with a pinion 68. The pinion 68 is fixed on ashaft 69 that is journalled in bearings '74 depending from the platform61). The shaft 69 has a ratchet wheel 71 at its end remote from thepinion 63. Turning the handwheel 66 can be done by the handle 72 or byturning the ratchet wheel 71.

To accomplish automatic turning of the ratchet wheel 71, I provide apawl 73 pivoted on a post 74. The post 74 is mounted on the base plate31 and holds the pawl in the path of the ratchet wheel 71. An adjustablestop 75 is threaded into the post 74 and leaf spring 76 fixed on thepost 74 yieldingly holds the pawl against the stop 75, but allows thepawl to slip over the teeth of the ratchet wheel 71 when the wheel ismoving away from the post 74. With this construction when the shaft 29is oscillated by the crank arm 28 and the rod 27, the grinder 35 ismoved in an arc to cause the wheel 62 to traverse each knife nose thatis moved past it by the head 2. At the finish of each stroke of thegrinder 355 toward the post 74, the pawl 73 engages the ratchet wheel 71and turns it a fraction of a turn. This causes the pinion 68 to turn thehandwheel 66 which will advance the motor 61 and grinding wheel 62toward the path of the noses of the knives 40. The grinding Wheel 62 canalways be brought to the work or away from it by turning the handwheel66 whenever the pawl 73 is out of engagement with the ratchet wheel 71.

The grinding unit 38 is supported to swing toward and away from the axisof the head 2 on an upright arm 73 which is fixed on a shaft 80 that isournalled in bearings 82 on the base 8. At the top of the arm '78 aplatform 83 is fixed. On this platform a motor 84 is slidably mounted inthe same manner as the motor 61 on the platform 60. The motor 84 carriesa grinding wheel 85. A handwheel 86 has its shaft 87 connected to themotor 34 in the same manner as the shaft 63 is connected to the motor61. A pinion 88 is fixed on a shaft 89 that is suspended by bearings 9t)and $1 from the platform 33. The pinion S8 meshes with the teeth 86a onthe handwheel 86. The shaft 89 has a ratchet wheel 92 fixed thereon. Apost 93 fixed on the base 8 carries a pawl 94 that is adapted to engagethe wheel 92 as the platform 83 moves toward the post 93. The pawl 94engages an adjustable stop 95 on the post 93 and is yieldingly heldagainst the stop by a leaf spring 96 fixed to the post 93. In order toswing the platform to and fro the rod 37 is pivotally connected to theplatform 83.

It is believed that the construction of my chipper knife grinder will beclear from the foregoing description. To grind a set of seven right handknives 40 and seven left hand knives 40 alike, the several knives areclamped in the channels 49 and 50. The grinding wheeis 62 and are movedby hand, adjusting the handwheels 66 and 86 until the wheels contact thework. Then the motors 9,. 61 and 84 are started and the grindingcontinues until the knives are sufficiently sharpened. The head 2rotates the several knives past the grinding wheels 2 and 85 at a rapidrate (for example, 50 rpm), while the wheels are rotated at high speedby their mo tors 61 and 84 respectively. The rods 27 and 37 are actuatedby the shaft 23 to reciprocate the units 35 and 38 to and fro slowly.The pawls '73 and 94 engage their respective ratchet wheels 71 and 92.just before the termination of the reciprocating movement in onedirection to advance the grinding wheels for the next stroke across thework and back.

Having described my invention, I claim:

1. A grinder for chipper knives comprising in combination, a base, aknife carrying head, a shaft supported for rotation on said base andcarrying said head, a pluraliity of knife carrying blocks on said headequally spaced from the shaft axis, each block including means to clampthereon a knife having a planar portion and an upturned nose thereonwith the cutting edges of the planar portions of the knives in a planeperpendicular to the shaft and the noses of the knives facing outwardlyand re ceding from said plane, a first grinding unit mounted on saidbase for reciprocal movement in a direction perpendicular to said shaft,and having a grinding wheel facing toward said head, means toreciprocate said grinding unit, a second grinding unit mounted on saidbase for reciprocating movement about an axis substantially tangent tothe path of rotation of the blocks and means to reciprocate said secondgrinding unit.

2. The invention defined in claim 1, together with means operable by thefirst and the second grinding units to advance them toward the knives atthe end of each reciprocation thereof.

3. The invention defined in claim 1 wherein the said clamping meanscomprises slots in said blocks open toward the first grinding unit andopen radially outward, clamp bars mounted in said slots and means toforce each clamp bar against a knife placed in the slot in which the baris mounted.

4. The invention defined in claim 1 wherein the means to reciprocatesaid grinding units comprise a common drive shaft, a horizontal shaftpivoted on the base, arm means pivoted on said horizontal shaft andcarrying the first grinding unit, a crank arm on the common drive shaftlinked to said arm means, a vertical shaft pivoted on the base andcarrying the second grinding unit, and crank arms and a link connectingthe vertical shaft to the common shaft.

References Cited in the file of this patent UNITED STATES PATENTSl,032,758 Lumsden July 16, 1912 1,039,075 Smith Sept. 17, 1912 1,781,674Ashworth Nov, 18, 1930

